title: Filamentary rod-shaped granules in Clara cells of rats.
abstract: The bronchiolar Clara cells of rats contain characteristic rod-shaped granules always surrounded by a unit membrane. These granules contain thin filaments about 9 to 10 nm in diameter lying in a pale matrix. Our morphological results suggest that the filamentary rod-shaped granules originate from the common, round-to-oval, electron-dense Clara cell granules, as we found different intermediate structures between these two kinds of granules. The electron-dense granules are digested by pepsin, whereas the filamentary rod-shaped granules are apparently not affected. The biochemical nature and the possible function of the filamentary rod-shaped granules are also discussed in relation to the secretory activity of the Clara cells.
mesh_terms: D000818:Animals; D001980:Bronchi / Q000648:ultrastructure*; D003594:Cytoplasmic Granules / Q000378:metabolism / Q000648:ultrastructure; D004847:Epithelial Cells; D004848:Epithelium / Q000648:ultrastructure; D005260:Female; D008297:Male; D010434:Pepsin A / Q000378:metabolism; D051381:Rats; D011919:Rats, Inbred Strains
chemical_list: D010434:Pepsin A